This study was conducted at the field of the College of Agricultural Engineering Sciences/ University of Duhok/ Duhok Governorate, for the season 2018-2019, the aim of this study was to determine the effect of different grain sizes and different methods of seed rate using different equations with two varieties of bread wheat (Triticum aestivum L.) on the performance of vegetative growth of bread wheat, by using R.C.B.D design with three replicates each replicate had (16) plots, the study consisted of three factors : the first factor were two varieties of wheat (Tammuz 2 and Adana 99). The second factor consisted of two grain sizes, medium and large and the third factor was consisted four different equations to estimate seeding rate . Results revealed that wheat varieties (Tammuz 2 and Adana 99) differed significantly in some vegetative growth traits as in plant height, number of emerged seedlings , number of tillers without spikes, flag leaf area, Total chlorophyll content, Grain size had no significant effect on vegetative growth traits except for number of tillers with spikes. Seeding rate estimation methods were significantly affected on traits emerged seedlings and number of tillers without spikes only. Interaction between grain size and variety showed a significant effect on plant height, number of emerged seedlings, number of tillers with spikes, flag leaf area and total chlorophyll content. Interaction between variety and methods of estimation seeding rate had a significant impact on most of the vegetative traits as in plant height, number of emerged seedlings, number of tillers without spikes, flag leaf area and total chlorophyll, but had no effect on the other traits. Interaction between size and methods of estimation emerged seeding rate had a significant impact on some vegetative growth traits as number of emerged seedlings, number of tillers with spikes and number of tillers without spikes. Triple interaction of variety with grain size with methods of estimation seeding rate had a significant impact for all the vegetative growth traits excluding leaf area index.